GH4706合金在不同时效下的析出相演化及其对力学性能的影响

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Abstract：This study systematically investigates the effects of different aging temperatures （ 600∘C and 650°C ） andaging times （3000h、5000h、10000h）on the microstructural evolution，room-temperature tensile properties， and high-temperature stress rupture properties of GH4706 alloy. The results indicate that the microstructure coarsens significantly with increasing aging temperature and time， with the grain size reaching 125μm after aging at 650∘C×10000h . Following high-temperature aging， the grain boundary n phase evolves rapidly from dispersed particles into a continuous network， while the intragranular carbides （primarily MC and M23C6 types）undergo continuous coarsening. This process is most severe under the 650∘C×10000h condition. The study reveals that during room-temperature tensile testing，theelongation after fracture is more sensitive to temperature，whereas the ultimate tensile strength is more sensitive to time.The high-temperature stress ruptureperformance is critically dependent on the precipitates at the grain boundaries; M23C6 carbides and the n phase act synergistically to promote crack initiation and propagation， leading to a drastic reduction in the stress rupture life of the 650∘C×10000h sample.In conclusion，the core mechanism behind the performance degradation of GH47o6 alloy during hightemperature long-termserviceis grain boundaryembritlement，inducedbythecombined effects of thecontinuous network of grain boundarynphase and the coarsening of carbides，which collctively deteriorate its mechanical properties.

Keywords： GH4706 alloy; aging treatment; microstructural evolution; precipitates phase; mechanical properties

1序言

GH4706合金是一种以Fe-Ni为基体的沉淀强化型高温合金，通过γ相和γ”相强化提升其高温力学性能[1-3]。（剩余8420字）